>>As far as a coloured filter on the lens, I don't believe that has any bearing on the issue of how the RGB meter functions. Let's take my white flower, without a filter it photographs white. If I put a red filter on, it photographs as red (well probably pink, but you get the idea). What the meter detects is the same as if I were taking a picture of a pink flower.<< Actually it DOES make a difference with strong filtration, such as one would use with B&W film Nikon states that error may occur when using this type of filtration with the matrix color metering system, since it biases it's reading based on color of subject ( green grass, blue sky, etc. ). Color correction filtration shouldn't affect it all that much, however. Pete